1. Field of the Invention
Methods and apparatuses consistent with the present invention relate to providing and receiving three-dimensional (3D) digital contents, and more particularly, to a method and apparatus for providing and receiving 3D digital contents by using a conventional system for providing two-dimensional (2D) digital contents
2. Description of the Related Art
As high-quality digital motion picture services have become more popular, an increasing interest in more realistic virtual reality services has led to research and development of encoding and decoding of 3D digital contents, such as 3D motion pictures, in three dimensions according to temporal and spatial characteristics.
Image coding methods in formats such as moving picture experts group (MPEG)-4 Part 2 and H.264 Advanced Video Coding (AVC) are for coding 2D images and are focused on improving coding efficiency. However, methods of coding and reconstructing images are required in fields such as realistic telecommunications or virtual reality.
Therefore, the MPEG working group, a standard organization regarding image encoding, is endeavoring to set a standard in relation to 3D audio/video (3D AV) encoding.
FIG. 1 is a diagram showing a conventional method of providing 2D reference images and 3D additional information.
Referring to FIG. 1, a structure of a program map table (PMT) section of a transport stream (TS) packet is shown.
In related art, a program and a program element descriptor are added to the PMT and left/right image signals are separated into packetized elementary stream (PES) packets of each of the left/right image signals in order to insert 3D image information in the TS. In FIG. 1, a left image is referred as a reference image 110, and a right image is referred as 3D additional information 120.
The left/right image signals refer to image signals used in case where a stereoscopic format 3D image is generated by using a left-view image and a right-view image to encode a 3D image. In this case, the left-view image is set as base layer video, and the right-view image is set as enhancement layer video. The base layer video is an image which can be encoded into a 2D image by itself, whereas the enhancement layer video is an image additionally required for generating a 3D image by being added to the base layer video.
In this case, introducing a new system for broadcasting 3D digital contents imposes technological and financial burdens, and the new system's compatibility with conventional 2D digital broadcasting systems may also become an issue. Thus, a method for resolving the aforementioned problems is required.